Z.Dtbl = function(param) {
    this.construir(param);
};

Z.Dtbl.prototype = {
    myDataTable : null,
    hello : function() {
        return this.myDataTable;
    },
    construir : function(parama) {
        this.myDataTable = parama;
    }
}

Y.util.Event.onDOMReady(function() {
    Context.dtbl = new Z.Dtbl("HI");
    Context.dtbl2 = new Z.Dtbl("BYE");
    alert(Context.dtbl.hello());
    alert(Context.dtbl2.hello());
});